COINCIDENCE OR PROPHECY? A GEOLOGICAL ANALYSIS OF JOHN MUIR’S FAMOUS ACCOUNT IN GLACIER BAY IN THE LATE 19TH CENTURY

The time of John Muir’s expeditions to Glacier Bay is of immense interest to the 100^thanniversary of the National Parks because it puts Muir’s critical observations into a broader perspective. By illuminating what the father of conservationism was truly seeing in the Bay, we can more thoroughly understand that which would inspire him to fight for the protection of American land. When John Muir visited Glacier Bay in 1879 he encountered immense melting, glacial retreat, and warming temperatures. The glaciers, he wrote, “are in the first stage of decadence, the waste from melting and evaporation being greater now than the supply of new ice from their snowy fountains.”

A developing network of climate sensitive ring-width and blue intensity tree–ring chronologies along the Gulf of Alaska and within Glacier Bay National Park and Preserve aid our understanding of the climate, both locally and synoptically, at the time of Muir’s expeditions. His timing also coincided with the transition from the Little Ice Age into the modern era of secular warming. These tree-ring chronologies also assist with reconstructing the glacial and ecological history within Glacier Bay at the time of Muir, allowing for direct comparison with Muir’s personal notes and sketches. In his journal notes Muir reports that Muir Glacier was resting relatively stably on its morainal bank, but would soon retreat into deeper water due to calving. While his namesake glacier was in this stable state, it enabled Muir to explore Tree Mountain on the glacier’s Southeastern margin. His sketches of Tree Mountain depict young trees whose growth during this time is reflected by a series of cores taken from the location in 2011. John Muir’s famous account of his late 19^th century visit to Glacier Bay was both influenced by climatological and geomorphic processes. However, the question remains if his observations were exaggerated by both the coincidental position and state of Muir Glacier in the tidewater glacier cycle and of warm intervals associated with decadal climate oscillations, or if they were deeply prophetic of a longer-term secular trend. It is possible then, that his account of Glacier Bay was most largely influenced by a coincidence of timing.